A section devoted when deemed necessary to cars the engine capacity of which does not exceed 1,000 c.c.
New 875-c.c. rear-engined O.H.C. Hillman Imp from Rootes' Scottish factory.
On May 3rd the rumours and counter-rumours about Rootes' great gamble, the Hillman Imp small car to be built ultimately at the rate of 150,000 a year at a brand-new and very modern factory on a 278-acre Rootes' site at Linwood near Glasgow (where rurality has been sacrificed to build virtually a new town) were quelled, for this was the announcement date. Prior to this one French paper and two English monthly motor papers had "jumped the gun" with illustrations and technical information and a weekly contemporary had courteously changed its publication date by a day in order to carry a description of this interesting new small car.
The release date was unfortunate for Motor Sport, nor were we invited to the opening of the new factory by H.R.H. The Duke of Edinburgh on May 2nd, although I have seen most of the big European car-producing plants. After driving to Ryton-on-Dunsmore for the announcement I drove an Imp a mere ten miles; I had been unable to persuade the Rootes Group to let me have a pre-announcement road-test car. I set down these points in order to explain why the following account of this much-discussed newcomer to the ranks of British small cars is more abbreviated than I would have wished.
The project began some five years ago with a smaller-engined prototype and developed at a cost of some £2-million, has evolved into an 875-cc, rear-engined 4-seater saloon which is to be built in basically one form at the Linwood works, giving initial employment to 5,000 people. The object is to provide very economical and practical transport of a thoroughly reliable nature, and for the time being the Hillman Imp will not be officially entered for competitions. I think its first rally appearance on a "works" basis will be in the 1964 Monte Carlo Rally.
Outstanding aspects of this little car, which costs £532 4s. 7d. in de luxe form, inclusive of p.t., are a light-alloy 4-cylinder o.h.c. in-line 3-bearing water-cooled "oversquare" engine of Coventry-Climax origin laid almost horizontal in the rear boot, an all-synchromesh 4-speed gearbox, i.r.s. by trailing-links instead of the customary swing-axles, i.f.s. by unusual bowed swing axles, coil-springs and telescopic dampers all round, oil-sealed rack-and-pinion steering, 8-in. dia. drum brakes, 12-in. wheels shod with Dunlop C41 tubeless tyres, a 6-gallon fuel tank under the floor of the front luggage boot, and a 2-door body, built by Pressed Steel at their plant opposite to the Linwood factory, which embodies several ingenious features. It is broadly true to say that the Imp has borrowed something of N.S.U. Prinz styling, a touch of Austin A40 Countryman, the cooling system of the Fiat 600, the heat-exchanger of a Simca 1000, the rigid interior stowage pockets of a B.M.C. Mini and B.M.W. rear suspension. Broadly, I emphasise. The ordinary Imp is priced at only £508 1s. 3d., p.t. paid, the basic price a mere £420, of which the light-alloy power unit accounts for some £230. It is undercut by the B.M.C. Mini and Mini Super de luxe, Citroën Bijou, Fiat 500D, Fiat 600D, Renault 4 and 4L, and in de luxe form, additionally by the B.M.C. Mini Countryman, Ford Anglia, MG. Midget, Morris Minor 1000, Moskvitch 407 (by 2d.), N.S.U. Prinz 4 de luxe, Bianchina, and Skoda Oktavia.
The engine really is a light-alloy unit, block, head, sutmp and and all major castings being of high- or low-pressure die-castings made in a 65,200 sq. ft. aluminium die-casting plant unique in British Industry. Gearbox and clutch housing are also of light alloy. The 875-c.c. engine is expected to be used for several years, but a more powerful (2-carburetter?) version may be developed, when the Imp should be exceptionally fast, reminiscent of those B.M.W. 700s that trounced the Minis at Silverstone some years ago. The normal unit, with a bore and stroke of 68 x 60.3 mm., has the high cr. of 10 to 1, a single automatic-choke Solex 30 PHIT carburetter, and develops 42 gross b.h.p. (39 net b.h.p.) at 5,000 r.p.m. and a maximum torque of 52 lb./ft. at 2,800 r.p.m. An o.h. camshaft (chain-driven) was desirable with the light-alloy construction and the latter was necessitated by the longitudinal rear mounting of the in-line engine. The engine weighs 170 lb., the transmission unit, with oil, 65 lb.
Cooling is by a radiator set beside the engine on its near-side, a la Fiat 600 and Simca 1000, with a 9-blade polypropolene fan cowled into it. There is a centrifugal pump and the coolant capacity is 6 3/4 pints. The sump holds 5 1/2 pints of oil.
The drive goes via a very light 5 1/2-in. Laycock diaphragm clutch to a delightful gearbox controlled by a short central floor lever, giving ratios of 16.6, 8.9, 5.7 and 4.13 to 1, top being indirect. Final drive is by hypoid crown-wheel and pinion and half-shafts with rubber couplings and universal joints. There are no greasing points on the car and routine servicing is required only at 5,000-mile intervals. The speedometer cable is driven from a front wheel and Rootes claim to have taken steps to ensure that it is not liable to breakages. Dunlop pneumatic throttle operation is an interesting item of detail.
The Hillman Imp has a wheelbase of 6 ft. 10 in., is 11 ft. 7 in. long, turns in 30 ft. 6 in., the steering calling for 2 3/4 turns lock-to-lock, and has a dry weight of fractionally over 13 1/4 cwt., equal to 61 b.h.p./ton. A small Lucas 12-volt. 32 amp. hr. battery, fuse-box and starter solenoid are accessible on the off-side of the engine compartment. The plugs are very accessible on the inclined engine, the dip-stick rather less so, and difficult to read. Tyre pressures are 15 lb./sq. in. front, double this at the rear, and Rootes say the suspension is susceptible to "tuning" by those who like to fiddle.
The 2-door saloon body has winding windows and simple quarter-lights in the doors, fixed rear side windows, but a lift-up rear window to facilitate loading or carrying difficult-size objects. The rear-seat squab folds flat to give 12 1/2 cu. ft. luggage space, with another 4 cu. ft. between front and rear seats. Normally, the front boot holds over 3 cu. ft. of luggage, the well behind the back seat in excess of 5 cu. ft. Fuel filler and brake-fluid reservoir are on the leading edge of the front boot, the water filler on the radiator and oil filler on the valve cover. There is a small interior lamp on the screen-sill, with neat push-pull switch, a good mirror and twin soft vizors, but no courtesy action of interior lighting. The engine compartment closes easily and when open is lit at night. The from seats are separate, tipping to provide access to the rear bench seat. Pedals are off-set and the wheel arches intrude into the front compartment.
There is carpeting on the floor and interior stowage borrows Issigonis' idea of four rigid side wells (longer, shallower, more rigid than on a Mini) and a lipped under-facia shelf. A hooded 90-m.p.h. speedometer incorporates the usual warning lights and odometer with decimals, and a slow-reading fuel gauge. Two convenient stalk controls close to the 2-spoke steering wheel look after (left) dipped and main headlamp beams and daylight flashing, and (right) turn indicators and horn. Very clearly labelled heater settings are provided for the single control adjacent to the driver's left foot, supplemented by a fan-switch on the facia and volume lever on the screen sill. Flick switches select lamps and wipers, with a rubber washers' button on the left side of the speedometer nacelle. Some of these switches are rather scattered considering their complementary functions. In lieu of back side window vents there is venting above the rear window. Knee and head room is restricted in the back seats. Some items apply only to the de luxe model.
It is interesting that the complete power pack can be removed by experts in ten minutes and trolleyed away on its own back wheels, and can be taken out and replaced in an hour by a service station.
The total pre-view run amounted to 40 miles of fairly normal terrain, but in this distance I judged the ride of the Imp to fall somewhere between that of a Mini and a Morris 1100, and the handling qualities to be very good, but inferior to those of a B.M.C. front-drive small car. There appeared to be understeer on trailing or steady throttle, which changed to oversteer as power was turned on. Some fan-noise was evident. The gear-change is absolutely outstanding and the ride round last corners notably flat. The speedometer is marked with cautious maxima of 20, 34, 50 and 88 m.p.h. in the gears but indicated speeds of 30, 50, 70 and 80 m.p.h. come up very readily. The test car had safety belts. At speed there was considerable shake at the facia and steering wheel.
Rootes claim acceleration figures of 0-30 m.p.h. in 6 sec., 0-40 in 9 1/2 Sec., 0-50 in 15-15 1/2 sec. and 0-60 m.p.h. in 23-24 1/2 sec., and in top gear 20-40 in 13-14 sec., 30-50 in 14-15 sec. and 40-60 m.p.h. in 18-19 sec., in which cog it is possible to slog away from 10 m.p.h. Such acceleration should just about dispose of opposition from normal B.M.C. Minibricks. 1,000 r.p.m. in top gear represents 15.3 m.p.h. so that at 70 m.p.h. (the claimed maximum is 75 m.p.h.) the engine is doing 4,600 r.p.m., and at the same speed in 3rd gear 6,400 r.p.m. Rootes say that it is difficult to make petrol consumption, not necessarily of 100-octane fuel, fall below 40 m.p.g. and that at high but steady speeds on Canadian throughways over 50 m.p.g. is being obtained.
Mr. Peter Ware, Chief Executive Engineer of the Rootes Group, conducted a very fair Press Conference about this new Hillman Imp from which it is obvious that the design team set its sights high, believes implicitly in a rear-engine location, trailing-link i.r.s. and water cooling, and has tested the little car, the first automobile to be made in Scotland for thirty years, with great thoroughness, at M.I.R.A., in Canada, Scandinavia, Switzerland, Spain, Kenya, France and Germany, as well as on home ground.
When an Imp is put at Motor Sport's disposal for a sufficiently long period I hope to submit it to a proper road-test and appraisal on the test track.—W. B.
Press comments on the Imp
Until we conduct a road-test of our own on the much-discussed "belated British pocket Volkswagen" (with apologies to Wolfsburg) we can but summarise the findings of the two privileged Trade journals which were allowed to carry full test reports in their release-day issues. It appears that if the handbook instructions are adhered to the Hillman Imp has maxima in the gears of only 20, 34 and 52 m.p.h. and a top speed of 70 m.p.h. It exceeds its maker's creditable acceleration figures but the fuel consumption claims may prove optimistic; the first journal to fully test an Imp obtained an overall figure of 38.1 m.p.g. Their criticisms were confined to fuel starvation on M1, the need for a pint of water every 300 miles or so (which should make exponents of air-cooling smile broadly!), occasional stalling when the engine was hot, almost too-light throttle action causing snatching on rough roads, poor geometry of the pendant clutch pedal, extraordinary vibration and shaking over pave and washboard, together with suspension noise and violent jolts over pot-holes, lack of structural rigidity in the scuttle, resulting in shaking of this, the instrument panel and steering wheel (which we also experienced), need for brake adjustment in 1,000 miles, a shallow front-boot, a rather high driving position, steering column too close to the brake pedal and rather broad screen-pillars.
The second full test report to be published was far more favourable, although scuttle and steering shake, limited luggage space in the front boot, a tendency for the engine to stall occasionally, a lot of steering kick-back on rough roads, heavy steering towards full lock, good average brakes that lost power clown a steep 1/2-mile hill and after a water-splash, some fan and road-wheel noise, insensitive hearer control and possibility that dust and fumes may be sucked in at the back window, were mentioned. This report included a table comparing the Imp with four competitive cars. On maximum speed the Imp just beat the Ford Anglia, on fuel consumption it was last behind the B.M.C. Mini, Anglia, N.S.U. Prinz 4 and Simca 1100, but it scored notably on 0-50 m.p.h. acceleration, leaving the Anglia nearly 2 sec, behind, and tied with the Mini in respect of 20-40 m.p.h. top-gear acceleration. If, however, the Renault R8 is included, it vanquishes the Imp on speed, and 0-50 and top-gear acceleration. Overall fuel consumption was 35.1 m.p.g. and London rush-hour traffic brought this down to 25 m.p.g.
We prefer to form our own opinions but, writing before we have driven an Imp for a four-figure mileage, it seems as if the baby Hillman has a very good engine, a superb gearbox, commands great respect for its infrequent servicing needs, has debatable handling qualities, is distinctly on the small side, not altogether quiet nor very good-looking (cheeky but too much top-hamper) but is competitively priced. On the whole, B.M.C, Renault and VW would seem to have little to fear... but extended experience of this interesting newcomer may well revise this opinion. [For a pictorial comparison of small car i.r.s., see page 417—Ed.]